Look at http://www.obd-codes.com/p0402
The code is Egr flow is excessive. You have replaced the two most likely causes. Disconnect the vacuum line to the EGR and drive the car see if it then surges. On some Honda and Acuras the EGR passages in the intake manifold plug up or get restricted and dump all the EGR into one or two cylinders causing them to misfire (go lean) on acceleration not sure if this is a Ford issue as well. There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online

Thanks for your reply. Will try. Recently the outside air temp dropped and the car had remarkable improvement. Only A few misses on acceleration.This happened after the engine had completely warmed. In the afternoon a 30 degree increase the engine began to surge and miss.